1. Field of the Invention
The present invention relates to an object information acquisition apparatus, a display method, and a computer-readable medium storing a program. In particular, the present invention relates to a technique for displaying distribution information acquired by transmitting elastic waves to an object and receiving reflected waves from the object.
2. Description of the Related Art
In the field of ultrasonography, which is an ultrasound-based imaging technique used for object information acquisition, an ultrasonograph is known to transmit ultrasonic waves (elastic waves) to an object. In response thereof, the ultrasonograph receives reflected waves reflected inside the object, and acquires an ultrasonic echo image, based on the pulse echo method. Japanese Patent Application Laid-Open No. 2012-24133 discusses an apparatus for generating an ultrasonic image (especially moving image) by applying delay and sum, envelope detection, etc., to a plurality of received signals acquired by receiving ultrasonic waves. With the apparatus discussed in Japanese Patent Application Laid-Open No. 2012-24133, when a user specifies an area to be enlarged as a Region Of Interest (ROI), an enlarged image of the specified area is displayed on a display unit. To optimize image quality, the user can specify whether to apply filtering to data of the enlarged image.
With the apparatus discussed in Japanese Patent Application Laid-Open No. 2012-24133, the displayed enlarged image is acquired by applying envelope detection to scanning line signals (echo data) having undergone delay and sum, as with the image before enlargement. However, an image acquired through such process is considered to provide limited visibility even after enlargement.
The user may specify an intra-object observation range in the depth direction (distance in the transmission direction of ultrasonic beams) as a similar operation to an enlarging operation. If the user specifies a depth range in this manner, the enlargement rate for image display changes according to the specified depth range and a display area in the screen of the display unit. Specifically, when the size of the display area is predetermined, specifying up to a shallow position as an observation range in the depth direction provides an intra-object image enlarged to a further extent than specifying up to a deep position. In this case, a similar problem to that in the enlarging operation arises, and an acquired image is considered to provide limited visibility depending on the specified depth range.